Methane asphyxia. Coal mine accident investigation of distribution of gas.

Death from asphyxia due to substitution of air by methane gas may occur in coal mine by gas outburst. In such a case, it is required to determine methane gas contents from cadaveric blood and tissues for diagnosing cause of death and estimating conditions of the accident. The methane concentration in blood and tissue samples of 22 male victims by a gas outburst accident was measured by gas chromatography. The level of methane in the cardiac blood was in the range of 6.8-26.8 microliters/g. As a model of gas outburst in coal mine, rats were exposed experimentally to various concentrations of methane. Their course of death and methane distribution in the bodies were observed. From these findings, diagnostic criteria for asphyxia from substitution of air by methane are also discussed.